Edit 2: I still haven't found a solution for the halved or less framerate but I found a solution for the block ghosting when using Haste 2 and and Efficiency 5 netherite/gold/diamond pikcaxe. Just break one of the blocks making up the top layer of your Haste 2 beacon, wait for the effect to run out, and replace the block. Haste 2 should come back without having to spend any more valuables since you didn't break the beacon and the ghosting from instantly breaking blocks in survival should be fixed at least 95% of the time

Moving from 1.18.30 to 1.18.31, my average FPS at all settings was cut to between 1/4th worst-case scenario and 1/2 best case scenario no matter what settings I run. I can't mine more than 2 blocks at a time without at least 1 block reappearing, unbroken, less than a second later (Edit: this only applies to mining with Haste 2, Efficiency 5 Diamond/Netherite tools as far as I've tested). I found a few other lag-based performance issues and the sort. Also, my GPU usage wildly fluctuates between 0% usage and 100% usage but averaging 50% usage even in really demanding situations Bottom line, with the inability to break blocks when I mine them and the game-breaking lag I plan on sitting out the game for a bit. 

The system I run:
Laptop (MSI GL65 Leopard 10UH)
RTX 2070 Max-P Mobile
i7-10750h (6 core/12 thread, 5.0 GHz Turbo)
16gb (2x8, 2666MHz) ram

I usually play with a 512x512 texture pack at 4k resolution with RTX and DLSS and get 30fps to 60fps depending on how demanding the zone is, currently at those settings I get 10fps to 25fps

I tried all setting variations including RTX on/off, I tested various resolutions by changing my monitor resolution including 1080p, 1440p, and 2160p(4k), and I also tested various high-resolution texture packs including standard texture pack, 64x64, 128x128, 256x256, 512x 512, and 1024x1024. No matter what settings, resolution, or texture pack I ran, I always got a bare minimum performance deduction of 50%. I also tried reverting to earlier GeForce drivers and tried different Nvidia Control Panel settings without* change. 

Edit: The reason I know it's a Minecraft issue and not a hardware issue is because no other game titles or system functions are affected and issues only appeared from the first time I loaded the game after the auto-update to 1.18.31 and continue as of making this edit/post